US5064474A - Process for removing fine particles from articles of fluorine-containing resin - Google Patents
Process for removing fine particles from articles of fluorine-containing resin Download PDFInfo
- Publication number
- US5064474A US5064474A US07/586,775 US58677590A US5064474A US 5064474 A US5064474 A US 5064474A US 58677590 A US58677590 A US 58677590A US 5064474 A US5064474 A US 5064474A
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- United States
- Prior art keywords
- cleaning
- fluorine
- article
- bottle
- procedure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- 238000000034 method Methods 0.000 title claims abstract description 78
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 title claims abstract description 55
- 229910052731 fluorine Inorganic materials 0.000 title claims abstract description 55
- 239000011737 fluorine Substances 0.000 title claims abstract description 55
- 239000011347 resin Substances 0.000 title claims abstract description 41
- 229920005989 resin Polymers 0.000 title claims abstract description 41
- 239000010419 fine particle Substances 0.000 title claims abstract description 28
- 239000007864 aqueous solution Substances 0.000 claims abstract description 21
- 239000012298 atmosphere Substances 0.000 claims abstract description 17
- 239000002798 polar solvent Substances 0.000 claims abstract description 11
- 239000007789 gas Substances 0.000 claims description 49
- 239000002904 solvent Substances 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 125000004432 carbon atom Chemical group C* 0.000 claims description 7
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims description 7
- 239000012459 cleaning agent Substances 0.000 claims description 5
- 229910020323 ClF3 Inorganic materials 0.000 claims description 4
- JOHWNGGYGAVMGU-UHFFFAOYSA-N trifluorochlorine Chemical compound FCl(F)F JOHWNGGYGAVMGU-UHFFFAOYSA-N 0.000 claims description 4
- 229910014264 BrF Inorganic materials 0.000 claims description 3
- 229910014263 BrF3 Inorganic materials 0.000 claims description 3
- 229910014271 BrF5 Inorganic materials 0.000 claims description 3
- 229910020313 ClF Inorganic materials 0.000 claims description 3
- 125000000217 alkyl group Chemical group 0.000 claims description 3
- XHVUVQAANZKEKF-UHFFFAOYSA-N bromine pentafluoride Chemical compound FBr(F)(F)(F)F XHVUVQAANZKEKF-UHFFFAOYSA-N 0.000 claims description 3
- 150000001735 carboxylic acids Chemical class 0.000 claims description 3
- TVWHTOUAJSGEKT-UHFFFAOYSA-N chlorine trioxide Chemical compound [O]Cl(=O)=O TVWHTOUAJSGEKT-UHFFFAOYSA-N 0.000 claims description 3
- OMRRUNXAWXNVFW-UHFFFAOYSA-N fluoridochlorine Chemical compound ClF OMRRUNXAWXNVFW-UHFFFAOYSA-N 0.000 claims description 3
- 239000012025 fluorinating agent Substances 0.000 claims description 3
- 125000001183 hydrocarbyl group Chemical group 0.000 claims description 3
- 150000002576 ketones Chemical class 0.000 claims description 3
- 230000008018 melting Effects 0.000 claims description 3
- 238000002844 melting Methods 0.000 claims description 3
- 239000007800 oxidant agent Substances 0.000 claims description 3
- FQFKTKUFHWNTBN-UHFFFAOYSA-N trifluoro-$l^{3}-bromane Chemical compound FBr(F)F FQFKTKUFHWNTBN-UHFFFAOYSA-N 0.000 claims description 3
- 150000001875 compounds Chemical class 0.000 claims description 2
- 238000004140 cleaning Methods 0.000 description 126
- 239000002245 particle Substances 0.000 description 33
- 229910021642 ultra pure water Inorganic materials 0.000 description 23
- 239000012498 ultrapure water Substances 0.000 description 23
- 230000000694 effects Effects 0.000 description 11
- 229910017900 NH4 F Inorganic materials 0.000 description 10
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 9
- 239000000047 product Substances 0.000 description 8
- 239000002253 acid Substances 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 230000014759 maintenance of location Effects 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 239000007795 chemical reaction product Substances 0.000 description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 230000000717 retained effect Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 235000019441 ethanol Nutrition 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 238000001039 wet etching Methods 0.000 description 2
- 229910003556 H2 SO4 Inorganic materials 0.000 description 1
- 229910003944 H3 PO4 Inorganic materials 0.000 description 1
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 1
- 229910017917 NH4 Cl Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- XSTXAVWGXDQKEL-UHFFFAOYSA-N Trichloroethylene Chemical group ClC=C(Cl)Cl XSTXAVWGXDQKEL-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 125000002947 alkylene group Chemical group 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- QSDQMOYYLXMEPS-UHFFFAOYSA-N dialuminium Chemical compound [Al]#[Al] QSDQMOYYLXMEPS-UHFFFAOYSA-N 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 229910001629 magnesium chloride Inorganic materials 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 235000011007 phosphoric acid Nutrition 0.000 description 1
- 150000003016 phosphoric acids Chemical class 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M potassium chloride Inorganic materials [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 239000011698 potassium fluoride Substances 0.000 description 1
- YGSFNCRAZOCNDJ-UHFFFAOYSA-N propan-2-one Chemical compound CC(C)=O.CC(C)=O YGSFNCRAZOCNDJ-UHFFFAOYSA-N 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 150000003460 sulfonic acids Chemical class 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- UBOXGVDOUJQMTN-UHFFFAOYSA-N trichloroethylene Natural products ClCC(Cl)Cl UBOXGVDOUJQMTN-UHFFFAOYSA-N 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
- 229910000368 zinc sulfate Inorganic materials 0.000 description 1
- 239000011686 zinc sulphate Substances 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
- C08J7/02—Chemical treatment or coating of shaped articles made of macromolecular substances with solvents, e.g. swelling agents
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
- C08J7/12—Chemical modification
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
- C08J7/12—Chemical modification
- C08J7/126—Halogenation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2327/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers
- C08J2327/02—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment
- C08J2327/12—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
Definitions
- the present invention relates to a process for removing particulate components deposited as impurities on the molded products of fluorine-containing resin.
- containers made of fluorine-containing resin are currently used for holding an agent for wet etching in production of semiconductors, i.e. representative products in the field of the high technology.
- These containers are usually cleaned with a dilute aqueous solution of a surfactant, strong acid, ultrapure water or the like, or when required, may be cleaned by supersonic treatment or immersion.
- a surfactant strong acid, ultrapure water or the like
- these methods can not achieve a satisfactory level of cleaning on containers of fluorine-containing resin, compared with the level on containers of polyethylene and therefore may be unempolyable for containers for holding an agent for wet etching or the like.
- the containers of fluorine-containing resin for holding a 50% aqueous solution of HF to be used in the manufacture of semiconductors must be cleaned to such an extent that after cleaning, 10 particles or less are contained in one milliliter of the solution in terms of the particles not smaller than 0.3 ⁇ m in particle size, and that after cleaning, one particle or less is contained in one milliliter thereof in terms of the particles not smaller than 0.5 ⁇ m in particle size.
- the cleaning with ultrapure water can not attain the above levels at all.
- containers of fluorine-containing resin are limited because they remain difficult to clean. Consequently such containers may become substantially out of use when a higher cleaning level is set in future.
- the present invention has been accomplished based on these novel findings.
- the fluorine-type gas used in the procedure (ii) is at least one gas selected from the group consisting of gases of F 2 , ClF 5 , ClF 3 , ClF, BrF 5 , BrF 3 , BrF, ClO 3 F, SF 4 , O 2 F 2 and NF 3 , the gas being one diluted or not diluted with an inactive gas;
- the polar solvent used in the procedure (iii) is at least one solvent selected from the group consisting of fluorine-containing carboxylic acids represented by the formula R f COOH (wherein R f is a fluorine-containing hydrocarbon group having 3 to 20 carbon atoms) and ketones represented by the formula R 1 COR 2 (wherein R 1 and R 2 are the same or different and each represent an alkyl group having 1 to 5 carbon atoms); and
- the methods of the invention essentially comprise subjecting an article of fluorine-containing resin to at least one of the procedures (i), (ii) and (iii).
- the procedures will be described below in greater detail.
- an article of fluorine-containing resin is maintained at a high temperature ranging from 100° C. to a temperature lower than the melting point of the article, preferably about 150° to about 260° C., to vaporize or scatter away the particles.
- the vaporization and scattering of particles can be beneficially accelerated by conducting an additional procedure such as rotation of article, agitation of atmosphere gas, spray of atmosphere gas, etc.
- the article is heated in air, a reaction product of particles and oxygen may deposit on the article at a high temperature, and the fluorine-containing resin may become impaired in properties.
- the article is, for example, placed into a heating oven and heated in the atmosphere of inactive gas.
- the retention time is not specifically limited and can be suitably determined depending on the degree of contamination of article, the required level of cleaning, etc. Usually it is about 10 to about 30 minutes.
- the procedure (i) may be executed either on a molded product of fluorine-containing resin or during the molding process of fluorine-containing resin.
- An article of fluorine-containing resin is maintained in the atmosphere of fluorine-type gas in this procedure. Beneficially the removal of particles can be accelerated by performing an additional procedure such as rotation of article, agitation of atmosphere gas, spray of atmosphere gas, etc.
- the fluorine-type gas may be filled into the container.
- Useful fluorine-type gases include gases capable of acting as a fluorinating agent or an oxidizing agent. Specific examples of such gases are gases of F 2 , ClF 5 , ClF 3 , ClF, BrF 5 , BrF 3 , BrF, ClO 3 F, SF 4 , O 2 F 2 , NF 3 , etc.
- gases are usable singly or at least two of them can be used in mixture.
- the gases may be used after dilution with an inactive gas.
- useful inactive gases for dilution are nitrogen, argon, helium, etc.
- a preferred concentration of the fluorine-type gas diluted with inactive gas is not lower than 0.1% by volume.
- the temperature of the fluorine-type gas atmosphere may be room temperature and is preferably elevated to accelerate the cleaning. The maximum elevated temperature is lower than the melting point of the article. The longer the retention time in the fluorine-type gas atmosphere, the higher the degree of cleaning is. However, the longer retention time is economically disadvantageous.
- the retention time although suitably determinable depending on the degree of contamination of article, the required level of cleaning, etc., is usually not shorter than 1 hour, preferably about 4 to 12 hours, in performing the procedure without heating, but about 10 to about 30 minutes in performing the procedure with heating.
- the cleaning in the atmosphere of fluorine-type gas may be effected either on a molded product of fluorine-containing resin or during the molding process of fluorine-containing resin.
- polar solvents useful in this procedure are fluorine-containing carboxylic acids represented by the formula R f COOH (wherein R f is a fluorine-containing hydrocarbon group having 3 to 20 carbon atoms, preferably 5 to 9 carbon atoms); ketones represented by the formula R 1 COR 2 (wherein R 1 and R 2 are the same or different and each represent an alkyl group having 1 to 5 carbon atoms); alcohols; amines and salts thereof; sulfonic acids; phosphoric acids and salts thereof; alkylene oxides; etc.
- the article is brought into contact with the solvent as by immersion of the article in the solvent and standing, by intensively spraying the solvent over the article, by causing the flow of the solvent or the movement of the article in order to promote the removal of particles, etc.
- Such flow or movement can be brought about as by shaking the solvent in the article (in case of container), or by immersing the article (in case of container) in the solvent and stirring the solvent or subjecting the solvent to circulating movement.
- the temperature of the solvent is usually in the range of about 35° to about 40° C.
- the degree of cleaning on articles of fluorine-containing resin can be also increased by performing an additional cleaning procedure at least once with ultrapure water and/or with a cleaning agent before or after, or both before and after, carrying out at least one of the procedures (i), (ii) and (iii).
- Useful cleaning agents include:
- acids and alkali-type agents such as aqueous solutions containing at least one species selected from HF, NH 4 F, HCl, HNO 3 , H 2 O 2 , H 2 SO 4 , H 3 PO 4 and NH 3 ; and
- organic solvents such as trichloroethylene, methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, etc.
- the foregoing cleaning agents are stored in containers or tanks made of fluorine-containing resin or transported in pipes made of fluorine-containing resin for use in the field of manufacture of semiconductors.
- the degree of cleaning on articles of fluorine-containing resin can be also increased by conducting additional cleaning at least once with an aqueous solution of electrolyte at a high concentration (not lower than 0.5% by weight) before or after, or both before and after, performing at least one of the procedures (i), (ii) and (iii).
- aqueous solution of electrolyte at a high concentration (not lower than 0.5% by weight) before or after, or both before and after, performing at least one of the procedures (i), (ii) and (iii).
- useful electrolytes are NH 4 Cl, NH 4 F, KCl, KF, NaCl, MgCl 2 , MgCO 3 , ZnCl 2 , ZnSO 4 , FeCl 3 , AlCl 3 , Al 2 (SO 4 ) 3 , etc.
- the methods of the present invention are suitable for removing the fine particles from the fluorine-containing resin article which must be cleaned to a great extent, particularly articles of fluorine-containing resin such as containers, tanks, pipes, tubes, wafer carriers, etc. for use in the field of manufacture of semiconductors.
- the methods of the invention can produce a cleaning effect to an extent heretofore unattainable by conventional techniques, more specifically, to such level that after cleaning, 10 particles or less are contained in one milliliter of the solution held in a container of fluorine-containing resin in terms of the particles not smaller than 0.3 ⁇ m in particle size, and that after cleaning, one particle or less is contained in one milliliter thereof in the container in terms of particles not smaller than 0.5 ⁇ m in particle size. Therefore the methods of the invention can meet the requirement for higher cleaning levels to be expected in the field of manufacture of semiconductors and other fields.
- PFA bottle tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer
- FEP bottle tetrafluoroethylene-hexafluoropropylene copolymer
- the bottles were cleaned by pouring an appropriate quantity of ultrapure water into each bottle, shaking the bottle under the conditions of vibrational amplitude of 4 cm and the number of vibration of 160 vibrations/min for 5 minutes and allowing the bottle to stand.
- the number of fine particles was counted with use of a counter for counting the number of fine particles in liquid (trade name "RION KL-21", manufactured by RION Co., Ltd.**).
- Table 1 shows the number of fine particles present in ultrapure water and having a size of at least 0.3 ⁇ m or at least 0.5 ⁇ m after completion of each cleaning procedure.
- Table 1 shows how the number of fine particles changes through the intermediate stages in the cleaning method using ultrapure water which is one of the conventional cleaning techniques.
- a molded 0.5 l-PFA bottle and a molded 1 l-FEP bottle were cleaned once with ultrapure water in the same manner as in Comparison Example 1 and thereafter maintained at a high temperature in the atmospheric ambience under the following conditions.
- the bottles thus treated were further cleaned with ultrapure water four times in the same manner as in Comparison Example 1.
- a 40% aqueous solution of NH 4 F or a 50% aqueous solution of HF was used for washing the bottles by the same procedure as in Comparison Example 1.
- Table 1 The comparison between Table 1 and Table 2 reveals that the number of fine particles is reduced by maintaining the molded bottles made of fluorine-containing resin in an atmosphere of high temperature. Presumably, this is because the particulate component present in the fluorine-containing resin evaporates off in an atmosphere of high temperature.
- a molded 0.5 l-PFA bottle was cleaned once with ultrapure water in the same manner as in Comparison Example 1 and was maintained at a high temperature in the atmospheric ambience under the following conditions. The bottle was further cleaned four times with ultrapure water by the same procedure as in Comparison Example 1. Further, a 40% aqueous solution of NH 4 F was used for cleaning the bottle in the same manner as in Comparison Example 1.
- a molded 0.5 l-PFA bottle and a molded 1 l-FEP bottle were internally cleaned once with ultrapure water in the same manner as in Comparison Example 1.
- the bottles were charged with an F 2 -containing gas (15% F 2 -85% N 2 ) and were retained under the following conditions.
- a molded 0.5 l-PFA bottle was cleaned with ultrapure water once by the same procedure as in Comparison Example 1. Thereafter the bottle was charged with an F 2 -containing gas (15% F 2 -85% N 2 ) and maintained under the following conditions.
- reaction product is introduced into the polymer of fluorine-containing resin and integrated with the bottle.
- a molded 0.5 l-PFA bottle and a molded 1 l-FEP bottle were internally cleaned with ultrapure water once in the same manner as in Comparison Example 1 and treated with ⁇ -hydrocarboxylic acid [H(CF 2 CF 2 ) 3 COOH] or acetone [CH 3 COCH 3 ].
- Such treatment was conducted by pouring ⁇ -hydrocarboxylic acid or acetone into the bottle and shaking the bottle under the conditions of a vibrational amplitude of 4 cm and the number of vibration of 160 vibrations/min for 5 minutes.
- the bottle was further cleaned four times with ultrapure water in the same manner as in Comparison Example 1. Thereafter, a 40% aqueous solution of NH 4 F or a 50% aqueous solution of HF was used for cleaning the bottles.
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Cleaning Or Drying Semiconductors (AREA)
- Treatments Of Macromolecular Shaped Articles (AREA)
- Cleaning By Liquid Or Steam (AREA)
- Cleaning In General (AREA)
- Detergent Compositions (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
The invention provides a method for removing the fine particles deposited on an article of fluorine-containing resin, the method comprising conducting at least one of the procedures of:
(i) maintaining the article of fluorine-containing resin at a high temperature,
(ii) maintaining the article in the atmosphere of fluorine-containing gas, and
(iii) bringing the article into contact with a polar solvent or an aqueous solution of polar solvent.
Description
The present invention relates to a process for removing particulate components deposited as impurities on the molded products of fluorine-containing resin.
Currently even fine particles of submicron size must be removed from the molded products of fluorine-containing resin in the field of the so-called high technology. Further, a demand for higher degree of cleaning is expected to increase.
For example, containers made of fluorine-containing resin are currently used for holding an agent for wet etching in production of semiconductors, i.e. representative products in the field of the high technology. These containers are usually cleaned with a dilute aqueous solution of a surfactant, strong acid, ultrapure water or the like, or when required, may be cleaned by supersonic treatment or immersion. These methods, however, can not achieve a satisfactory level of cleaning on containers of fluorine-containing resin, compared with the level on containers of polyethylene and therefore may be unempolyable for containers for holding an agent for wet etching or the like.
More specifically, the containers of fluorine-containing resin for holding a 50% aqueous solution of HF to be used in the manufacture of semiconductors must be cleaned to such an extent that after cleaning, 10 particles or less are contained in one milliliter of the solution in terms of the particles not smaller than 0.3 μm in particle size, and that after cleaning, one particle or less is contained in one milliliter thereof in terms of the particles not smaller than 0.5 μm in particle size. The cleaning with ultrapure water can not attain the above levels at all.
Use of containers of fluorine-containing resin is limited because they remain difficult to clean. Consequently such containers may become substantially out of use when a higher cleaning level is set in future.
It is an object of the present invention to provide a method for removing the particulate components as impurities from the molded products of fluorine-containing resin.
Other objects and features of the invention will become apparent from the following description.
In view of the aforesaid state of the art, we conducted extensive research and found that the fine particles can be effectively removed from an article of fluorine-containing resin when the article is maintained at a high temperature.
Our another finding was that a similar particle-removing effect can be also produced when the article is maintained in the atmosphere of a specific fluorine-type gas.
Our additional finding was that a similar particle-removing effect can be also achieved when the article is brought into contact with a specific solvent.
The present invention has been accomplished based on these novel findings.
According to the the present invention, there are provided:
(1) a method for removing the fine particles deposited on an article of fluorine-containing resin, the method comprising conducting at least one of the procedures of:
(i) maintaining the article of fluorine-containing resin at a high temperature,
(ii) maintaining the article in the atmosphere of fluorine-type gas, and
(iii) bringing the article into contact with a polar solvent or an aqueous solution of polar solvent;
(2) a method as defined above in item (1) in which the article is maintained at a temperature of not lower than 150° C. in the procedure (i);
(3) a method as defined above in item (1) in which the fluorine-type gas used in the procedure (ii) is a type of gas capable of acting as a fluorinating agent or an oxidizing agent;
(4) a method as defined above in item (3) in which the fluorine-type gas used in the procedure (ii) is at least one gas selected from the group consisting of gases of F2, ClF5, ClF3, ClF, BrF5, BrF3, BrF, ClO3 F, SF4, O2 F2 and NF3, the gas being one diluted or not diluted with an inactive gas;
(5) a method as defined above in item (3) or (4) in which the gas is maintained at a temperature higher than room temperature in the procedure (ii);
(6) a method as defined above in item (1) in which the polar solvent used in the procedure (iii) is at least one solvent selected from the group consisting of fluorine-containing carboxylic acids represented by the formula Rf COOH (wherein Rf is a fluorine-containing hydrocarbon group having 3 to 20 carbon atoms) and ketones represented by the formula R1 COR2 (wherein R1 and R2 are the same or different and each represent an alkyl group having 1 to 5 carbon atoms); and
(7) a method as defined above in item (1) in which the article is cleaned at least once with ultrapure water and/or with a cleaning agent before or after, or both before and after, conducting at least one of the procedures (i), (ii) and (iii).
The methods of the invention essentially comprise subjecting an article of fluorine-containing resin to at least one of the procedures (i), (ii) and (iii). The procedures will be described below in greater detail.
In this procedure, an article of fluorine-containing resin is maintained at a high temperature ranging from 100° C. to a temperature lower than the melting point of the article, preferably about 150° to about 260° C., to vaporize or scatter away the particles. The vaporization and scattering of particles can be beneficially accelerated by conducting an additional procedure such as rotation of article, agitation of atmosphere gas, spray of atmosphere gas, etc. When the article is heated in air, a reaction product of particles and oxygen may deposit on the article at a high temperature, and the fluorine-containing resin may become impaired in properties. To avoid this possibility, preferably the article is, for example, placed into a heating oven and heated in the atmosphere of inactive gas. The longer the retention time at a high temperature, the higher the degree of cleaning is but with economical disadvantage. The retention time is not specifically limited and can be suitably determined depending on the degree of contamination of article, the required level of cleaning, etc. Usually it is about 10 to about 30 minutes.
The procedure (i) may be executed either on a molded product of fluorine-containing resin or during the molding process of fluorine-containing resin.
An article of fluorine-containing resin is maintained in the atmosphere of fluorine-type gas in this procedure. Beneficially the removal of particles can be accelerated by performing an additional procedure such as rotation of article, agitation of atmosphere gas, spray of atmosphere gas, etc. In case the article of fluorine-containing resin is a container, the fluorine-type gas may be filled into the container. Useful fluorine-type gases include gases capable of acting as a fluorinating agent or an oxidizing agent. Specific examples of such gases are gases of F2, ClF5, ClF3, ClF, BrF5, BrF3, BrF, ClO3 F, SF4, O2 F2, NF3, etc. These gases are usable singly or at least two of them can be used in mixture. The gases may be used after dilution with an inactive gas. Examples of useful inactive gases for dilution are nitrogen, argon, helium, etc. A preferred concentration of the fluorine-type gas diluted with inactive gas is not lower than 0.1% by volume. The temperature of the fluorine-type gas atmosphere may be room temperature and is preferably elevated to accelerate the cleaning. The maximum elevated temperature is lower than the melting point of the article. The longer the retention time in the fluorine-type gas atmosphere, the higher the degree of cleaning is. However, the longer retention time is economically disadvantageous. The retention time, although suitably determinable depending on the degree of contamination of article, the required level of cleaning, etc., is usually not shorter than 1 hour, preferably about 4 to 12 hours, in performing the procedure without heating, but about 10 to about 30 minutes in performing the procedure with heating.
The cleaning in the atmosphere of fluorine-type gas may be effected either on a molded product of fluorine-containing resin or during the molding process of fluorine-containing resin.
In this procedure, an article of fluorine-containing resin is cleaned by being brought into contact with a polar solvent or an aqueous solution of polar solvent (hereinafter referred to simply as "solvent" if not necessary). Examples of polar solvents useful in this procedure are fluorine-containing carboxylic acids represented by the formula Rf COOH (wherein Rf is a fluorine-containing hydrocarbon group having 3 to 20 carbon atoms, preferably 5 to 9 carbon atoms); ketones represented by the formula R1 COR2 (wherein R1 and R2 are the same or different and each represent an alkyl group having 1 to 5 carbon atoms); alcohols; amines and salts thereof; sulfonic acids; phosphoric acids and salts thereof; alkylene oxides; etc. Stated more specifically, the article is brought into contact with the solvent as by immersion of the article in the solvent and standing, by intensively spraying the solvent over the article, by causing the flow of the solvent or the movement of the article in order to promote the removal of particles, etc. Such flow or movement can be brought about as by shaking the solvent in the article (in case of container), or by immersing the article (in case of container) in the solvent and stirring the solvent or subjecting the solvent to circulating movement. As the temperature of the solvent is raised during the cleaning, a higher cleaning effect is produced but with economical disadvantage. For this reason, the temperature of the solvent is usually in the range of about 35° to about 40° C.
The degree of cleaning on articles of fluorine-containing resin can be also increased by performing an additional cleaning procedure at least once with ultrapure water and/or with a cleaning agent before or after, or both before and after, carrying out at least one of the procedures (i), (ii) and (iii). Useful cleaning agents include:
(a) acids and alkali-type agents such as aqueous solutions containing at least one species selected from HF, NH4 F, HCl, HNO3, H2 O2, H2 SO4, H3 PO4 and NH3 ; and
(b) organic solvents such as trichloroethylene, methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, etc.
The foregoing cleaning agents are stored in containers or tanks made of fluorine-containing resin or transported in pipes made of fluorine-containing resin for use in the field of manufacture of semiconductors.
The degree of cleaning on articles of fluorine-containing resin can be also increased by conducting additional cleaning at least once with an aqueous solution of electrolyte at a high concentration (not lower than 0.5% by weight) before or after, or both before and after, performing at least one of the procedures (i), (ii) and (iii). Examples of useful electrolytes are NH4 Cl, NH4 F, KCl, KF, NaCl, MgCl2, MgCO3, ZnCl2, ZnSO4, FeCl3, AlCl3, Al2 (SO4)3, etc.
The methods of the present invention are suitable for removing the fine particles from the fluorine-containing resin article which must be cleaned to a great extent, particularly articles of fluorine-containing resin such as containers, tanks, pipes, tubes, wafer carriers, etc. for use in the field of manufacture of semiconductors.
The following great advantages can be offered by cleaning an article of fluorine-containing resin according to the present invention.
(A) The methods of the invention can produce a cleaning effect to an extent heretofore unattainable by conventional techniques, more specifically, to such level that after cleaning, 10 particles or less are contained in one milliliter of the solution held in a container of fluorine-containing resin in terms of the particles not smaller than 0.3 μm in particle size, and that after cleaning, one particle or less is contained in one milliliter thereof in the container in terms of particles not smaller than 0.5 μm in particle size. Therefore the methods of the invention can meet the requirement for higher cleaning levels to be expected in the field of manufacture of semiconductors and other fields.
(B) If the procedure (i) or (ii) in the methods of the invention is carried out during molding of fluorine-containing resin, a cleaning procedure need not be conducted on the molded product.
Given below are Examples and Comparison Examples to clarify the features of the present invention in greater detail.
Two kinds of molded bottles each made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (hereinafter referred to as "PFA bottle") and tetrafluoroethylene-hexafluoropropylene copolymer (hereinafter referred to as "FEP bottle"), respectively were cleaned with ultrapure water (specific resistance [MΩ.cm at 25° C.]: at least 18, number of fine particles [number of particles/ml, having a size of not smaller than 0.3 μm]: 1 or less, T.O.C. [ppb]: 10 to 100, ultrapure water of this type will be also used hereinafter) in the order as shown below in Table 1.
The bottles were cleaned by pouring an appropriate quantity of ultrapure water into each bottle, shaking the bottle under the conditions of vibrational amplitude of 4 cm and the number of vibration of 160 vibrations/min for 5 minutes and allowing the bottle to stand. The number of fine particles was counted with use of a counter for counting the number of fine particles in liquid (trade name "RION KL-21", manufactured by RION Co., Ltd.**). Table 1 shows the number of fine particles present in ultrapure water and having a size of at least 0.3 μm or at least 0.5 μm after completion of each cleaning procedure.
Further, a 40% aqueous solution of NH4 F or a 50% aqueous solution of HF from which fine particles were removed beforehand by filtration using a filter (0.1 μm) was poured into the bottles for cleaning the bottles internally thereof in the same manner as above. Table 1 also shows the number of fine particles counted in this case.
In the following Examples and Comparison Examples, cleaning with ultrapure water was conducted in the same manner as in this Comparison Example unless otherwise specified. Further, 40% aqueous solutions of NH4 F and 50% aqueous solutions of HF were filtered by the same procedure as above and used in the following cleaning operations.
Each value shown in the following tables and obtained using PFA bottles is the average of two data determined by actual count, and that obtained using FEP bottles is the average of three such data.
TABLE 1
__________________________________________________________________________
0.5 l Bottle
1 l Bottle
1 l Bottle
of PFA of FEP of FEP
Particle size
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
__________________________________________________________________________
Number of fine particles
Cleaning with super-
pure water
1st cleaning (np*/ml)
2894 440 1380 556 2257 864
Procedure of invention
None
2nd cleaning (np/ml)
401 25.4 681 69.8 1980 1084
3rd cleaning (np/ml)
135 3.4 209 16.1 1697 696
4th cleaning (np/ml)
47.2 1.5 226 31.7 1226 467
5th cleaning (np/ml)
16.1 0.5 112 14.8 770 319
Cleaning with 40% NH.sub.4 F
1st cleaning (np/ml)
80.0 9.0 207 14.1 -- --
2nd cleaning (np/ml)
13.3 1.3 167 14.7 -- --
Cleaning with 50% HF
1st cleaning (np/ml)
-- -- -- -- 173 12.2
2nd cleaning (np/ml)
-- -- -- -- 29.5 1.1
__________________________________________________________________________
*The mark "np" means the number of particles
Table 1 shows how the number of fine particles changes through the intermediate stages in the cleaning method using ultrapure water which is one of the conventional cleaning techniques.
In the following Examples and Comparison Examples, the degree of the improvement of cleaning effect is evaluated by comparison with the results shown in Table 1.
A molded 0.5 l-PFA bottle and a molded 1 l-FEP bottle were cleaned once with ultrapure water in the same manner as in Comparison Example 1 and thereafter maintained at a high temperature in the atmospheric ambience under the following conditions. The bottles thus treated were further cleaned with ultrapure water four times in the same manner as in Comparison Example 1. Furthermore, a 40% aqueous solution of NH4 F or a 50% aqueous solution of HF was used for washing the bottles by the same procedure as in Comparison Example 1.
*0.5 l-PFA bottle
Temperature: 250° C.
Time: 30 min
*1 l-FEP bottle
Temperature: 200° C.
Time: 30 min
Table 2 shows the results.
TABLE 2
__________________________________________________________________________
0.5 l Bottle
1 l Bottle
1 l Bottle
of PFA of FEP of FEP
Temperature 250° C.
200° C.
200° C.
Particle size
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
__________________________________________________________________________
Number of fine particles
Cleaning with super-
pure water
1st cleaning (np*/ml)
2701 339 966 274 2457 479
Procedure of Invention
Maintained at high temperature
2nd cleaning (np/ml)
51.1 1.1 70.1 2.3 176 2.0
3rd cleaning (np/ml)
4.0 0.5 14.6 1.7 51.6 2.0
4th cleaning (np/ml)
4.1 0.3 10.1 0.8 27.3 0.7
5th cleaning (np/ml)
3.3 0.1 7.8 0.2 37.0 0.8
Cleaning with 40% NH.sub.4 F
1st cleaning (np/ml)
22.8 3.8 18.8 0.5 -- --
2nd cleaning (np/ml)
6.8 0.6 19.4 0.6 -- --
Cleaning with 50% HF
1st cleaning (np/ml)
-- -- -- -- 9.1 1.2
2nd cleaning (np/ml)
-- -- -- -- 2.9 0.3
__________________________________________________________________________
*The mark "np" means the number of particles
The comparison between Table 1 and Table 2 reveals that the number of fine particles is reduced by maintaining the molded bottles made of fluorine-containing resin in an atmosphere of high temperature. Presumably, this is because the particulate component present in the fluorine-containing resin evaporates off in an atmosphere of high temperature.
After cleaned once with ultrapure water in the same manner as in Comparison Example 1, a molded 0.5 l-PFA bottle was maintained at a high temperature in the atmospheric ambience under the following conditions. Thereafter the bottle was further cleaned four times with ultrapure water by the same procedure as in Comparison Example 1. Moreover, a 40% aqueous solution of NH4 F was used for washing the bottle in the same manner as in Comparison Example 1.
Temperature: 150° C., 200° C. and 250° C.
Time: 30 min
Table 3 shows the results.
TABLE 3
__________________________________________________________________________
0.5 l Bottle
0.5 l Bottle
0.5 l Bottle
of PFA of PFA of PFA
Condition (150° C., 30 min.)
(200° C., 30 min.)
(250° C., 30 min.)
Particle size
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
__________________________________________________________________________
Number of fine particles
Cleaning with super-
pure water
1st cleaning (np*/ml)
1721 233 2428 34.1 2701 339
Procedure of Invention
Maintained at high temperature
2nd cleaning (np/ml)
371 25.3 244 9.8 51.1 1.1
3rd cleaning (np/ml)
127 6.9 23.7 1.2 4.0 0.5
4th cleaning (np/ml)
74.6 2.4 13.8 0.6 4.1 0.3
5th cleaning (np/ml)
48.9 1.2 11.5 0.6 3.3 0.1
Cleaning with 40% NH.sub.4 F
1st cleaning (np/ml)
93.1 14.4 69.6 12.0 22.8 3.8
2nd cleaning (np/ml)
18.4 1.3 12.4 1.1 6.8 0.6
__________________________________________________________________________
*The mark "np" means the number of particles
(Note) Data at 250° C. are the same as in Table 2
By comparison between the results as shown in Table 1 and those shown in Table 3 with respect to 0.5 l-PFA bottle, it is clear that the effect of removing fine particles is improved with the rise of the temperature. Since the particulate component is removed by evaporation in this Example, it is desirable to heat the bottles at a higher temperature insofar as the applied temperature does not adversely affect the bottles.
A molded 0.5 l-PFA bottle was cleaned once with ultrapure water in the same manner as in Comparison Example 1 and was maintained at a high temperature in the atmospheric ambience under the following conditions. The bottle was further cleaned four times with ultrapure water by the same procedure as in Comparison Example 1. Further, a 40% aqueous solution of NH4 F was used for cleaning the bottle in the same manner as in Comparison Example 1.
Temperature 250° C.
Time: 0.5 min, 1 min, 5 min, 10 min and 30 min
Table 4 shows the results.
TABLE 4
__________________________________________________________________________
0.5 l Bottle
0.5 l Bottle
0.5 l Bottle
0.5 l Bottle
0.5 l Bottle
of PFA of PFA of PFA of PFA of PFA
Condition (250° C., 0.5 min.)
(250° C., 1 min.)
(250° C., 5 min.)
(250° C., 10
(250° C., 30
min.)
Particle size
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5
≧0.3
≧0.5
μm
__________________________________________________________________________
Number of fine particles
Cleaning with super-
pure water
1st cleaning (np*/ml)
1040 84.4 426 33.1 1276 155 773 69.3 2701 339
Procedure of Invention
Maintained at high temperature
2nd cleaning (np/ml)
89.1 1.8 37.5 0.8 58.4 1.7 18.1 0.7 51.1 1.1
3rd cleaning (np/ml)
41.9 0.9 15.2 0.6 33.7 1.0 7.6 0.6 4.0 0.5
4th cleaning (np/ml)
20.1 0.4 10.3 0.3 9.6 0.6 5.3 0.3 4.1 0.3
5th cleaning (np/ml)
9.2 0.2 7.2 0.2 5.3 0.1 3.0 0.1 3.3 0.1
Cleaning with 40% NH.sub.4 F
1st cleaning (np/ml)
44.9 1.9 26.0 1.9 13.7 0.9 12.0 1.3 22.8 3.8
2nd cleaning (np/ml)
10.4 0.5 8.2 0.5 4.6 0.1 4.4 0.1 6.8 0.6
__________________________________________________________________________
*The mark "np" means the number of particles
(Note) Data for 30 minutes are the same as in Table 2
By comparison between the results as shown in Table 1 and those shown in Table 4 with regard to the 0.5 l-PFA bottle, it is revealed that when the bottle is maintained at 250° C., the number of fine particles is reduced by maintaining the bottle for only 0.5 minute. When the bottle is maintained for 10 minutes or longer, a large number of fine particles evaporate off, whereby little or no quantity of fine particles remain.
A molded 0.5 l-PFA bottle and a molded 1 l-FEP bottle were internally cleaned once with ultrapure water in the same manner as in Comparison Example 1. The bottles were charged with an F2 -containing gas (15% F2 -85% N2) and were retained under the following conditions.
______________________________________
Time for which F.sub.2.sup.-
Heating Heating
containing gas was temperature
time
retained (hr) (°C.)
(min)
______________________________________
PFA, 0.5 l
12 30 --
PFA, 0.5 l
4 250 30
FEP, 1 l
4 200 30
FEP, 1 l
4 200 30
______________________________________
The bottles were further cleaned with ultrapure water four times by the same procedure as in Comparison Example 1. Moreover, a 40% aqueous solution of NH4 F or a 50% aqueous solution of HF was used for cleaning the bottles in the same manner as in Comparison Example 1.
Table 5 shows the results.
TABLE 5
__________________________________________________________________________
0.5 l Bottle of PFA
0.5 l Bottle of PFA
1 l Bottle of FEP
1 l Bottle of FEP
Temperature (about 30° C.)
(250° C.)
(200° C.)
(200° C.)
Particle size
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5
__________________________________________________________________________
μm
Number of fine particles
Cleaning with super-
pure water
1st cleaning (np*/ml)
531 41.1 1517 189 1598 239 2818 1169
Procedure of Invention
Maintained in fluorine gas atmosphere
2nd cleaning (np/ml)
17.4 2.9 67.1 14.1 50.8 14.4 34.0 4.4
3rd cleaning (np/ml)
5.0 0.9 6.7 0.7 5.9 1.0 9.8 1.0
4th cleaning (np/ml)
2.0 0.3 2.7 0.5 1.5 0.2 3.5 0.5
5th cleaning (np/ml)
1.4 0.1 2.2 0.3 1.1 0.3 3.4 0.3
Cleaning with 40% NH.sub.4 F
1st cleaning (np/ml)
9.5 1.2 17.1 3.0 17.1 3.1 -- --
2nd cleaning (np/ml)
4.2 0.7 2.7 0.4 6.7 1.0 -- --
Cleaning with 50% HF
1st cleaning (np/ml)
-- -- -- -- -- -- 1.7 0.5
2nd cleaning (np/ml)
-- -- -- -- -- -- 1.2 0.2
__________________________________________________________________________
*The mark "np" means the number of particles
The results as shown in Table 5 clearly indicate that the F2 -containing gas, when introduced into a container made of fluorine-containing resin, exhibits cleaning effect even at ordinary temperature.
A molded 0.5 l-PFA bottle was cleaned with ultrapure water once by the same procedure as in Comparison Example 1. Thereafter the bottle was charged with an F2 -containing gas (15% F2 -85% N2) and maintained under the following conditions.
______________________________________
Time for which F.sub.2.sup.-
Heating Heating
containing gas was
temperature
time
retained (hr) (°C.)
(min)
______________________________________
12 30 --
4 75 30
4 100 30
4 125 30
4 150 30
4 200 30
4 250 30
______________________________________
Then the bottle was further cleaned with ultrapure water four times in the same manner as in Comparison Example 1. Moreover, a 40% aqueous solution of NH4 F was used for cleaning the bottle by the same procedure as in Comparison Example 1.
Table 6 shows the results.
TABLE 6
__________________________________________________________________________
0.5 l Bottle
0.5 l Bottle
0.5 l Bottle
0.5 l Bottle
0.5 l Bottle
0.5 l Bottle
0.5 l Bottle
of PFA of PFA
of PFA
of PFA
of PFA
of PFA
of PFA
Temperature (about 30° C.)
(75° C.)
(100° C.)
(125° C.)
(150° C.)
(200° C.)
(250° C.)
≧0.3
≧0.5
≧0.3
≧0.5
≧0.3
≧0.5
≧0.3
≧0.5
≧0.3
≧0.5
≧0.3
≧0.5
≧0.3
≧0.5
Particle size
μm
μm
μm
μm
μm
μm
μm
μm
μm
μm
μm
μm
μm
μm
__________________________________________________________________________
Number of fine particles
Cleaning with super-
pure water
1st cleaning (np*/ml)
531 41.1
2905
412
1569
204
822
93.8
2132
250
1994
234
1517
189
Procedure of Invention
Maintained in fluorine gas atmosphere
2nd cleaning (np/ml)
17.4
2.9
10.4
4.1
27.3
2.4
11.5
1.0
51.4
14.7
35.4
8.4
67.1
14.1
3rd cleaning (np/ml)
5.0 0.9
2.3
0.4
12.8
1.5
5.1
0.6
4.1
1.0
4.9
0.7
6.7
0.7
4th cleaning (np/ml)
2.0 0.3
2.4
0.6
5.6
0.8
2.7
0.2
5.1
1.2
3.3
0.3
2.7
0.5
5th cleaning (np/ml)
1.4 0.1
1.8
0.3
2.4
0.3
2.1
0.1
2.2
0.4
2.2
0.5
2.2
0.3
Cleaning with 40% NH.sub.4 F
1st cleaning (np/ml)
9.5 1.2
4.8
0.9
7.9
0.6
4.4
0.3
23.6
5.1
17.2
3.0
17.1
3.0
2nd cleaning (np/ml)
4.2 0.7
2.3
0.3
3.6
0.2
3.0
0.1
4.6
0.8
2.5
0.4
2.7
0.4
__________________________________________________________________________
*The mark "np" means the number of particles
(Note) Data at 250° C. are the same as in Table 5
The results shown in Table 6 indicate that a cleaning effect is recognized when the bottle made of fluorine-containing resin is filled with F2 -containing gas regardless of the temperature at which the bottle is maintained. This is because the particulate component present in the bottle reacts with the F2 -containing gas. Consequently, the particulate component is removed presumably by the following phenomena.
(a) A fluorine-containing compound is obtained as the reaction product, is lowered in boiling point and thus evaporates off.
(b) A reaction product high in solubility in water is obtained, markedly dissolved in ultrapure water and removed.
(c) The reaction product is introduced into the polymer of fluorine-containing resin and integrated with the bottle.
In Examples 4 and 5, use of a fluorine-containing gas such as ClF3, NF3 or the like in place of the F2 -containing gas produces substantially the same outstanding effect.
A molded 0.5 l-PFA bottle and a molded 1 l-FEP bottle were internally cleaned with ultrapure water once in the same manner as in Comparison Example 1 and treated with ω-hydrocarboxylic acid [H(CF2 CF2)3 COOH] or acetone [CH3 COCH3 ]. Such treatment was conducted by pouring ω-hydrocarboxylic acid or acetone into the bottle and shaking the bottle under the conditions of a vibrational amplitude of 4 cm and the number of vibration of 160 vibrations/min for 5 minutes.
In order to evaluate the effect produced by the treatment with the above solvents, the bottle was further cleaned four times with ultrapure water in the same manner as in Comparison Example 1. Thereafter, a 40% aqueous solution of NH4 F or a 50% aqueous solution of HF was used for cleaning the bottles.
Table 7 shows the results.
TABLE 7
__________________________________________________________________________
0.5 l Bottle of PFA 1 l Bottle of FEP
ω-Hydrocarboxylic
0.5 l Bottle of PFA
ω-Hydrocarboxylic
acid Acetone acid
Solvent H(CF.sub.2 CF.sub.2).sub.3 COOH
CH.sub.3 COCH.sub.3
H(CF.sub.2 CF.sub.2).sub.3 COOH
Particle size
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
__________________________________________________________________________
Number of fine particles
Cleaning with super-
pure water
1st cleaning (np*/ml)
1895 235 2836 407 968 361
Procedure of Invention
Contacted with Solvent
2nd cleaning (np/ml)
13.6 0.8 51.8 1.8 221 57.8
3rd cleaning (np/ml)
6.8 1.2 46.4 2.9 34.5 2.3
4th cleaning (np/ml)
2.5 0.6 18.0 0.9 4.6 0.4
5th cleaning (np/ml)
3.1 0.7 10.6 0.7 6.5 1.5
Cleaning with 40% NH.sub.4 F
1st cleaning (np/ml)
38.0 3.9 50.6 11.4 25.1 2.4
2nd cleaning (np/ml)
6.8 1.1 4.4 0.6 4.4 0.4
Cleaning with 50% HF
1st cleaning (np/ml)
-- -- -- -- -- --
2nd cleaning (np/ml)
-- -- -- -- -- --
__________________________________________________________________________
1 l Bottle of FEP
ω-Hydrocarboxylic
1 l Bottle of FEP
1 l Bottle of FEP
acid Acetone Acetone
Solvent H(CF.sub.2 CF.sub.2).sub.3 COOH
CH.sub.3 COCH.sub.3
CH.sub.3 COCH.sub.3
Particle size
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
≧0.3 μm
≧0.5 μm
__________________________________________________________________________
Number of fine particles
Cleaning with super-
pure water
1st cleaning (np*/ml)
2400 692 742 228 803 287
Procedure of Invention
Contacted with Solvent
2nd cleaning (np/ml)
9.6 0.2 60.2 2.1 26.3 7.1
3rd cleaning (np/ml)
15.6 1.1 43.6 1.7 83.9 30.4
4th cleaning (np/ml)
15.6 0.6 17.9 1.8 63.7 15.7
5th cleaning (np/ml)
19.2 0.8 10.3 0.6 19.0 8.8
Cleaning with 40% NH.sub.4 F
1st cleaning (np/ml)
-- -- 27.9 1.7 -- --
2nd cleaning (np/ml)
-- -- 29.4 1.8 -- --
Cleaning with 50% HF
1st cleaning (np/ml)
1.4 0 -- -- 4.8 1.2
2nd cleaning (np/ml)
1.7 0.1 -- -- 4.4 0.5
__________________________________________________________________________
*The mark "np" means the number of particles
The results shown in Table 7 clearly indicate that cleaning effect is remarkably improved by cleaning the molded bottle of fluorine-containing resin with the above solvent. This is presumably because the particulate component present in the molded product of fluorine-containing resin is dissolved in the solvent and removed.
Claims (7)
1. A method for removing the fine particles deposited on an article of fluorine-containing resin, the method comprising conducting at least one of the procedures of:
(i) maintaining the article of fluorine-containing resin at a temperature ranging from 100° C. to a temperature lower than the melting point of the article,
(ii) maintaining the article in the atmosphere of a gaseous compound containing fluorine, and
(iii) bringing the article into contact with a polar solvent or an aqueous solution of polar solvent in an amount sufficient to remove the fine particles.
2. A method as defined in claim 1 in which the article is maintained at a temperature of not lower than 150° C. in the procedure (i).
3. A method as defined in claim 1 in which the fluorine-containing gas used in the procedure (ii) is a gas capable of acting as a fluorinating agent or an oxidizing agent.
4. A method as defined in claim 3 in which the fluorine-containing gas used in the procedure (ii) is at least one gas selected from the group consisting of gases of F2, ClF5, ClF3, ClF, BrF5, BrF3, BrF, ClO3 F, SF4, O2 F2 and NF3, the gas being one diluted or not diluted with an inactive gas.
5. A method as defined in claim 3 in which the gas is maintained at a temperature higher than room temperature in the procedure (ii).
6. A method as defined in claim 1 in which the polar solvent used in the procedure (iii) is at least one solvent selected from the group consisting of fluorine-containing carboxylic acids represented by the formula Rf COOH (wherein Rf is a fluorine-containing hydrocarbon group having 3 to 20 carbon atoms) and ketones represented by the formula R1 COR2 (wherein R1 and R2 are the same or different and each represent an alkyl group having 1 to 5 carbon atoms).
7. A method as defined in claim 1 in which the article is cleaned at least once with superpure water and/or a cleaning agent before or after, or both before and after, conducting at least one of the procedures (i), (ii) and (iii).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1-251531 | 1989-09-26 | ||
| JP1251531A JPH085140B2 (en) | 1989-09-26 | 1989-09-26 | Fluororesin processing method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US5064474A true US5064474A (en) | 1991-11-12 |
Family
ID=17224196
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US07/586,775 Expired - Lifetime US5064474A (en) | 1989-09-26 | 1990-09-24 | Process for removing fine particles from articles of fluorine-containing resin |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5064474A (en) |
| EP (3) | EP0632088B1 (en) |
| JP (1) | JPH085140B2 (en) |
| KR (1) | KR0157321B1 (en) |
| DE (3) | DE69025837T2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5932673A (en) * | 1995-08-17 | 1999-08-03 | E. I. Du Pont De Nemours And Company | Tetrafluoroethylene copolymer |
| CN100517558C (en) * | 1998-03-25 | 2009-07-22 | 大金工业株式会社 | Method for washing fluororubber molded articles for semiconductor manufacturing equipment and washed molded articles |
| US20110117751A1 (en) * | 2008-03-07 | 2011-05-19 | Advanced Technology Materials, Inc. | Non-selective oxide etch wet clean composition and method of use |
| US12311417B2 (en) | 2018-11-27 | 2025-05-27 | Daikin Industries, Ltd. | Method and system for producing fluororesin molded article |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5158801A (en) * | 1988-04-01 | 1992-10-27 | The United States Of America As Represented By The United States Administrator Of The National Aeronautics And Space Administration | Method of forming a multiple layer dielectric and a hot film sensor therewith |
| US5213621A (en) * | 1991-10-11 | 1993-05-25 | Air Products And Chemicals, Inc. | Halogenated carboxylic acid cleaning agents for fabricating integrated circuits and a process for using the same |
| JP3275431B2 (en) * | 1993-03-25 | 2002-04-15 | ダイキン工業株式会社 | Fluororesin molded article and method for producing the same |
| US6113824A (en) * | 1997-06-20 | 2000-09-05 | Daikin Industries, Ltd. | Process for surface treating a fluorine-containing resin molded article |
| US7067616B2 (en) * | 2003-06-26 | 2006-06-27 | Advanced Technology Materials, Inc. | Polytetrafluoroethylene treatment |
| JP5381367B2 (en) * | 2009-06-15 | 2014-01-08 | 旭硝子株式会社 | Method for producing fluororesin molded body |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2059754A (en) * | 1979-10-04 | 1981-04-29 | Corval Machinery Ltd | Washing moulded plastics articles |
| US4711256A (en) * | 1985-04-19 | 1987-12-08 | Robert Kaiser | Method and apparatus for removal of small particles from a surface |
| US4787941A (en) * | 1986-06-30 | 1988-11-29 | Wang Laboratories, Inc. | Cleaning method for keyboard assemblies |
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| US4144218A (en) * | 1977-07-08 | 1979-03-13 | Hercules Incorporated | Thermosetting compositions containing a poly (arylacetylene) and a poly (phenylene oxide) |
| US4328044A (en) * | 1978-02-02 | 1982-05-04 | University Of Dayton | Method for cleaning metal parts |
| DD152921A1 (en) * | 1980-09-11 | 1981-12-16 | Heinz Werner | METHOD AND ARRANGEMENT FOR DISCONTINUING ON A SURFACE OF ATTACHING PARTICLES |
| US4680060A (en) * | 1985-09-20 | 1987-07-14 | The Coca-Cola Company | Process for the extraction of contaminants from plastics |
| JPS6345822A (en) * | 1986-08-13 | 1988-02-26 | Hitachi Ltd | Method and apparatus for cleaning |
| JPS63310063A (en) * | 1987-06-11 | 1988-12-19 | Matsushita Electric Ind Co Ltd | Layout display device |
| JP2541560B2 (en) * | 1987-06-12 | 1996-10-09 | 住友シチックス株式会社 | Cleaning method for fluororesin products |
| US4764405A (en) * | 1987-07-22 | 1988-08-16 | Air Products And Chemicals, Inc. | Method for increasing barrier properties of thermoplastic substrates |
| FR2632654B1 (en) * | 1988-06-09 | 1994-05-06 | Atochem | VINYLIDENE POLYFLUORIDE MATERIAL WITH A SURFACE SUITABLE FOR ADHERING TO A NON-COMPATIBLE POLYMER, METHOD OF SURFACE TREATMENT OF A VINYLIDENE POLYFLUORIDE MATERIAL TO ENABLE ADHERENCE TO A NON-COMPATIBLE POLYMER |
| BR8804580A (en) * | 1988-09-01 | 1990-01-23 | Mauro Sergio Curtis | PVC SURFACE TREATMENT PROCESS |
| DE3840269A1 (en) * | 1988-11-30 | 1990-05-31 | Messer Griesheim Gmbh | METHOD FOR PRODUCING SMOOTH SURFACES ON OBJECTS FROM POLYMERS OF ETHYLENE, PROPYLENE, BUTADIENE AND POLYSTYRENE |
-
1989
- 1989-09-26 JP JP1251531A patent/JPH085140B2/en not_active Expired - Fee Related
-
1990
- 1990-09-24 US US07/586,775 patent/US5064474A/en not_active Expired - Lifetime
- 1990-09-25 DE DE69025837T patent/DE69025837T2/en not_active Expired - Fee Related
- 1990-09-25 EP EP94113657A patent/EP0632088B1/en not_active Expired - Lifetime
- 1990-09-25 DE DE69032487T patent/DE69032487T2/en not_active Expired - Fee Related
- 1990-09-25 EP EP94113656A patent/EP0632089B1/en not_active Expired - Lifetime
- 1990-09-25 DE DE69032275T patent/DE69032275T2/en not_active Expired - Fee Related
- 1990-09-25 EP EP90118378A patent/EP0420141B1/en not_active Expired - Lifetime
- 1990-09-26 KR KR1019900015320A patent/KR0157321B1/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2059754A (en) * | 1979-10-04 | 1981-04-29 | Corval Machinery Ltd | Washing moulded plastics articles |
| US4711256A (en) * | 1985-04-19 | 1987-12-08 | Robert Kaiser | Method and apparatus for removal of small particles from a surface |
| US4787941A (en) * | 1986-06-30 | 1988-11-29 | Wang Laboratories, Inc. | Cleaning method for keyboard assemblies |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5932673A (en) * | 1995-08-17 | 1999-08-03 | E. I. Du Pont De Nemours And Company | Tetrafluoroethylene copolymer |
| CN100517558C (en) * | 1998-03-25 | 2009-07-22 | 大金工业株式会社 | Method for washing fluororubber molded articles for semiconductor manufacturing equipment and washed molded articles |
| US20110117751A1 (en) * | 2008-03-07 | 2011-05-19 | Advanced Technology Materials, Inc. | Non-selective oxide etch wet clean composition and method of use |
| US12311417B2 (en) | 2018-11-27 | 2025-05-27 | Daikin Industries, Ltd. | Method and system for producing fluororesin molded article |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH085140B2 (en) | 1996-01-24 |
| DE69025837T2 (en) | 1996-09-26 |
| EP0632089B1 (en) | 1998-07-15 |
| KR910005906A (en) | 1991-04-27 |
| DE69032275D1 (en) | 1998-05-28 |
| EP0632088B1 (en) | 1998-04-22 |
| JPH03112632A (en) | 1991-05-14 |
| EP0632089A1 (en) | 1995-01-04 |
| DE69032487D1 (en) | 1998-08-20 |
| EP0420141A2 (en) | 1991-04-03 |
| KR0157321B1 (en) | 1998-12-01 |
| DE69032487T2 (en) | 1999-01-07 |
| DE69032275T2 (en) | 1998-09-10 |
| DE69025837D1 (en) | 1996-04-18 |
| EP0420141B1 (en) | 1996-03-13 |
| EP0420141A3 (en) | 1991-10-23 |
| EP0632088A1 (en) | 1995-01-04 |
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